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671.
Growth of the ship-fouling diatom Amphora coffeaeformis and accumulation of copper in the cells were evaluated for cultures exposed to copper. Comparisons with literature reports for other species revealed that A. coffeaeformis shows no ability to maintain normal growth rates in the presence of high cellular copper levels. This suggests that internal binding is not the principal copper tolerance mechanism for this species. In addition, the copper complexing capacity of A. coffeaeformis exudates was evaluated. Significant complexing by these exudates was demonstrated by DPASV analysis. When added to the culture medium of another species (Thalassiosira profunda), A. coffeaeformis exudates were also able to reduce copper toxicity and accumulation in the cells of that species. However, the copper tolerance of A. coffeaeformis was greater than that acquired by T. profunda grown with A. coffeaeformis exudates; thus exudate production was deemed not to be a primary tolerance mechanism. Comparison of copper accumulations inside and outside cells of A. coeffeaeformis suggests that binding at the cell surface or to mucilage may be an important factor in the tolerance of this species to copper. 相似文献
672.
Environmental impact assessment (EIA) has been, and remains for the time being, a very important tool of environmental management — though not always for the reasons one would expect. Major achievements of EIA have been through indirect benefits that have had little recognition to date, particularly the achievements of its stimulative and educative roles. However, EIA is evolving as a planning tool and will continue to do so, and we argue that, in time, we will be able to go beyond EIA as a separate stand alone process. We indicate the requirements for its eventual absorption into project planning and design, and the concomitant need to fully incorporate environmental issues in land use planning to address those matters that cannot be addressed on a project-by-project basis. 相似文献
673.
A Decision-Support System for Prioritizing Restoration Sites on the Mississippi River Alluvial Plain 总被引:4,自引:0,他引:4
Daniel W. Llewellyn Gary P. Shaffer Nancy Jo Craig Lisa Creasman David Pashley Mark Swan Cindy Brown 《Conservation biology》1996,10(5):1446-1455
Conversion of forested wetlands to agricultural use and the resulting fragmentation of the landscape has led to concerns for the functional integrity of the Mississippi River Alluvial Plain ecosystem. We describe an effort spearheaded by The Nature Conservancy to initiate a multi-decade partnership dedicated to creating and implementing a viable, cooperative, landscape-level restoration project in the Mississippi River Alluvial Plain. Important phases of the process during the first 5 years were (1) initiation of the development of an extensive network of partners, including state and federal agencies, private land owners, conservation groups, academicians, and other interested citizens; (2) development of a geographic information system (GIS) for the entire extent of the ecosystem; and (3) for one watershed, the Tensas basin in northeastern Louisiana, refinement of a high resolution GIS to generate more detailed land-use conversion statistics to demonstrate the feasibility of a semi-objective, landscape-scale restoration planning procedure, including methodology for prioritization of existing wetland forest patches and areas most suitable for reforestation and connection via corridors. 相似文献
674.
Summary Variation in weight, wing length and bill length in a population of grey-crowned babblers is influenced primarily by sex and age, but correlations with size of social unit, with reproductive success, and with vegetation are also detectable (Table 1). The latter correlations vary with sex, age, and status as helper or breeder. Differential wear according to behavioral role, competition for status, incubation, and inheritance are discussed as possible causal mechanisms. Helpers were not detectably smaller in any dimension than breeders of the same age and sex. Male and female non-breeding helpers differ in patterns of morphological correlation, suggesting that they have different behavioral roles. Breeding males have a unique pattern of morphological correlation, suggesting that their foraging behavior differs from breeding females and non-breeders. 相似文献
675.
Genetic (allozyme) variation and population genetic structure of the rare shrub Daviesia suaveolens , found in only a few large populations on the eastern escarpment of the southern tablelands of New South Wales, were compared to those of its abundant and widespread relative D. mimosoides at both spatially equivalent and rangewide scales. We hypothesized that the rare species is genetically depauperate relative to the common one. We also generated baseline data on D. suaveolens to provide management recommendations for its conservation. Both species had high variation relative to other widespread woody angiosperms. Rangewide, the rare species exhibited lower species-level genetic variation than its common relative but a similar level of variation to that found in D. mimosoides over an equivalent spatial scale. Population-level genetic variation was similar for the two species. Over its small geographic range, D. suaveolens populations were three times as genetically differentiated as D. mimosoides over the same scale, showing a clear northsouth genetic disjunction and as much interpopulation divergence as the common species exhibited rangewide. These results confirm that not all types of rarity have the same genetic implications. Conservation strategies for D. suaveolens need not be concerned about low population-level variation unless populations become significantly smaller than is currently typical. Of more importance is to maintain the high interpopulation differentiation by conserving populations from both the north and south of the species' range. 相似文献
676.
Prenatal diagnosis of Gaucher disease, the most prevalent glycolipid storage disease, is based on a reliable enzyme assay of cells from amniocentesis or chorionic villous samples. However, this method cannot differentiate among the various forms of the disease. This report details four cases of prenatal diagnosis of Gaucher disease, three of which predate the use of molecular diagnosis. DNA mutation analysis to determine the genotype was predictive of the phenotypic status of the fetus and conformed to the genotype of an affected proband where available. 相似文献
677.
Since the 1970s, there has been a global proliferation of environmental courses. The types of courses are described, as are the structures, philosophies and objectives of courses which have stood the test of time. Employment of environmental graduates is discussed. The degree in Australian Environmental Studies (AES) from Griffith University is described and discussed with reference to pitfalls described in the literature. In Australia, there has been an increased demand for graduates in the environmental area. The trend in employers has been widening the field of potential recruits by keeping the degree specification broad and using the duty statements in the advertisements to specify the environmental skills and knowledge required. The number of graduates from AES has increased steadily since the course was established, and despite global and national trends of proliferation of environmental courses and graduates, survey results indicated that graduates from AES are professionally employed in a wide range of employment sectors, with female and male graduates being equally successful in obtaining employment. 相似文献
678.
Environmental education in Sweden 总被引:1,自引:1,他引:0
Summary Schools and higher education institutions in Sweden have developed a wide range of innovative and demanding curricula to meet the objectives of Sweden's environmental policy. Environmental education in compulsory schools is taught principally through biological sciences, although social studies are beginning to occupy a substantial component of the environmental curriculum. Upper secondary schools offer more opportunities to develop environmental awareness, understanding and practical skills than comparable sixth form and post-secondary colleges in England. In Sweden there is a strong emphasis on practical work developed through projects based on contemporary environmental issues and their resolution. The development of environmental education has been well supported by a substantial input of new resources, especially materials developed by the Swedish Environmental Protection Agency and Industry. Universities have also begun to adopt new organisational structures to help develop inter-disciplinary teaching and research teams. Several universities are experimenting with common core courses, parts of which comprise environmental elements.Dr P. Brown is currently Visiting Professor of Environmental Education, in the School of Natural Sciences at the University of Hertfordshire. All five authors were until recetly members of Her Majesty's Education Service Inspectorate. 相似文献
679.
680.
Charles J. Strobel John F. Paul Melissa M. Hughes Henry W. Buffum Barbara S. Brown J. Kevin Summers 《Environmental monitoring and assessment》2000,63(1):223-236
In the early 1990s, EPA's Environmental Monitoring and Assessment Program (EMAP) documented the ecological condition of the overall population of small estuaries along the mid-Atlantic coast of the United States. However, the Program did not provide detailed information on the condition of individual estuaries less than 260 km2 in surface area, a group of estuaries of concern to environmental managers. To address the needs of environmental managers, when EMAP returned to the region in summer 1997, it included a study of the spatial variability of ecological indicators within individual small estuaries. At 127 probability-based sites in 10 estuaries, EMAP measured a variety of parameters of water quality and sediments, including dissolved oxygen (DO), nutrients, grain size of sediments, contaminants in sediments, and community structures of benthic macroinvertebrates. From this information the ecological condition (e.g., percent area with DO concentrations below 5mg L–1) for each estuary, along with 90% confidence interval, was determined. The width of the confidence interval was then recalculated for sample sizes ranging from two stations to the total number of stations sampled in that estuary. Confidence interval widths were then plotted against sample size. These plots can be useful in designing future regional monitoring programs with a goal of describing conditions in individual systems as well as broad geographic regions. Results illustrate that beyond five stations per estuary, the reduction in the width of the confidence interval with increasing sampling intensity is relatively small; however, individual program managers need to determine "how small is small enough." 相似文献